IMPACT OF YEASTS AND THEIR DERIVATIVES ON THE GROWTH AND SURVIVAL OF PROBIOTIC BACTERIA

Abstract

This research investigated the effects of yeasts and/or inactivated yeast derivatives (IYDs) on the growth of probiotic bacteria in milk, and their survival at low pH conditions. Co-culturing Bifidobacterium animalis subsp. lactis HN019 with yeasts stimulated the growth and metabolic activities of the probiotic bacterium in a skim milk media, as well as increased the generation of various aroma compounds during fermentation. The viability of B. lactis in milk during incubation at 30 °C was also improved by the presence of yeasts. IYDs used in winemaking enhanced the survival of the Lactobacillus rhamnosus HN001 in a pH 3.0 buffer system. Supplementing IYDs into milk also accelerated the growth of various probiotic strains during fermentation. Co-inoculating Saccharomyces cerevisiae EC-1118 into non-supplemented and IYD-supplemented milks did not affect the growth of L. rhamnosus during fermentation. However, the survival of L. rhamnosus in fermented milks during storage was significantly enhanced by the presence of the yeast.